James Katz told jurors Friday at Bulger's trial that he took illegal bets on sporting events from 1971 to 1993. The 83-year-old Bulger is charged in a broad racketeering indictment with participating in 19 murders and committing other crimes.

Katz says he had to turn over customer fees on bets and an additional monthly fee to Bulger's gang.

Katz himself was indicted in the 1990s and says he initially refused to testify to a grand jury about the gang because he feared for his safety. He eventually testified after prosecutors offered him a reduced sentence and protection.

On Thursday, a retired state police colonel identified weapons found hidden in locations connected to Bulger as prosecutors at Bulger's racketeering trial showed jurors photos and videos of organized crime figures Bulger associated with and an arsenal of guns authorities say his gang used.

Retired state police Col. Thomas Foley Thursday identified weapons found during a 2000 investigation, including some in a shed behind a South Boston home owned by the mother of Bulger's partner, Stephen "The Rifleman" Flemmi. When investigators searched the shed, they found just one handgun, but later, Flemmi's son led them to a house in Somerville and a storage facility in Florida where investigators say the guns had been moved.

Foley methodically identified dozens of guns through photographs. But prosecutor Fred Wyshak pulled out six machine guns -- one at a time -- so jurors could see for themselves the kind of firepower Bulger's gang had at its disposal.

Foley also testified that the gang collected fees known as "rent" or "tribute" from bookmakers, drug dealers and others to allow them to operate within their territory. When Wyshak asked what the consequences were for not paying, Foley said, "Well, it could range from being put out of business to taking a beating, or actually at times, some people were killed."

Bulger, the former leader of the Winter Hill Gang, is charged with a long list of crimes in a 32-count racketeering indictment, including participating in 19 killings in the 1970s and '80s. He was one of the FBI's most wanted fugitives after he fled Boston in 1994.

Bulger, now 83, was captured in Santa Monica, Calif., in 2011.

Foley's testimony came after another retired state police officer, Lt. Robert Long, identified Bulger on several surveillance videos from 1980. The videos showed Bulger meeting with members of his gang, as well as assorted members of the Italian Mafia.

During cross-examination by Bulger's lawyer, Hank Brennan, Foley acknowledged that none of the weapons were found in Bulger's house and neither his fingerprints nor DNA were found on any of them.

Bulger's lead attorney, J.W. Carney Jr., conceded during opening statements Wednesday that Bulger corrupted FBI agents by paying them to tip him off about search warrants, bugs and indictments, but said Bulger was never an FBI informant, as prosecutors maintain.

Prosecutor Brian Kelly said Bulger made millions through drugs, extortion and loan-sharking by instilling fear in drug dealers, bookies and others. Kelly said Bulger was a long-time FBI informant who provided information on the New England Mafia, his gang's rivals.

Carney agreed with the prosecutor's description of how Bulger made his money, but insisted he was never an FBI informant and denied that he killed two 26-year-old women he is accused of strangling or businessmen in Florida and Oklahoma.